This disclosure is generally in the field of implantable medical devices and methods, more particularly in the field of drug delivery devices deployable within the bladder.
Systemic methods of drug delivery may produce undesirable side effects and may result in the distribution and metabolization of the drug by physiological processes, ultimately reducing the quantity of drug to reach the desired site. A variety of devices and methods have been developed to deliver drug in a more targeted manner, e.g., locally or regionally, which may address many of the problems associated with systemic drug delivery. Local delivery of drug to some tissue sites, however, has room for improvement, particularly with respect to extended drug delivery with minimally invasive devices and method and with minimum patient discomfort.
Interstitial cystitis (IC), painful bladder syndrome (PBS), and chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) are chronic painful disorders that are often treated by delivering a lidocaine solution to the bladder via instillation. To achieve sustained relief, repeated instillations may be required, such as three times per week for two weeks. The frequency of such instillations may be undesirable, as each instillation entails the inconvenience, discomfort, and risk of infection associated with urinary catheterization. Similarly, intermittent catheterization may be used to deliver drugs to the bladder that ease symptoms of neurogenic bladder. However, catheterization carries the drawbacks described above, among others. Thus, treatments could benefit from an intravesical drug delivery device that is implanted in the bladder.
Other therapies also could benefit from improved intravesical drug delivery devices, particularly where local delivery of a drug to the bladder is preferred or necessary—such as when the side effects associated with systemic delivery of the drug are intolerable and/or when bioavailability from oral administration is too low.
Situs Corporation developed an intravesical drug delivery system (UROS infuser device) for the delivery of pharmaceutical solutions of drugs, such as oxybutynin (for the treatment of overactive bladder) and mitomycin C (for the treatment of bladder cancer). The UROS infuser device and methods of implanting the device are disclosed in U.S. Pat. No. 6,171,298, No. 6,183,461, and No. 6,139,535. One problem with such devices is that the device is relatively large because a relatively large volume device is required to contain both a sufficient amount of the drug solution and the inlet/outlet valve mechanism.
Previous attempts at bladder drug delivery devices show that tolerability of the device in the bladder is a patient concern and a technical hurdle. For certain conditions or diseases, such as where the disease or condition is potentially fatal if left untreated (e.g., cancer), tolerability may be a secondary consideration. However, for other indications, tolerability may be a primary consideration. Unfortunately, known bladder devices, due perhaps to their large size or other mechanical characteristics, have not been well tolerated by patients and would be unsuitable in indications where tolerability is a primary concern, particularly where the treatment process would advisably require deployment and drug release over an extended period.
A need therefore exists for an intravesical drug delivery device that is sufficiently small to avoid unnecessary discomfort and pain during and following deployment of the device into patients, that can reduce the number of surgical or interventional procedures required for implantation and delivery of drug over the treatment period—e.g., that provides controlled delivery over an extended period, and that can carry an effective amount of drug for the extended period in a sufficiently small payload volume. In bladder applications, the device desirably should be retained in the bladder and not excreted before the drug payload can be at least substantially released, even when the drug needs to be delivered over a period of several days or weeks. In general, better devices are needed for controlled delivery of drug to the bladder. Desirably, the implantable device should be easy to deliver into (and if necessary, remove from) the bladder with reduced pain or discomfort to the patient.